KNEE

Surgical treatment for early osteoarthritis.Part II: allografts and concurrent procedures

A. H. Gomoll • G. Filardo • F. K. Almqvist • W. D. Bugbee • M. Jelic •

J. C. Monllau • G. Puddu • W. G. Rodkey • P. Verdonk • R. Verdonk •

S. Zaffagnini • M. Marcacci

Received: 3 August 2011 /Accepted: 6 October 2011 / Published online: 9 November 2011! Springer-Verlag 2011

Abstract Young patients with early osteoarthritis (OA)represent a challenging population due to a combination of

high functional demands and limited treatment options.

Conservative measures such as injection and physicaltherapy can provide short-term pain relief but are only

palliative in nature. Joint replacement, a successful pro-

cedure in the older population, is controversial in youngerpatients, who are less satisfied and experience higher

failure rates. Therefore, while traditionally not indicatedfor the treatment of OA, cartilage repair has become a

focus of increased interest due to its potential to provide

pain relief and alter the progression of degenerative dis-ease, with the hope of delaying or obviating the need for

joint replacement. The field of cartilage repair is seeing the

rapid development of new technologies that promisegreater ease of application, less demanding rehabilitation

and better outcomes. Concurrent procedures such as men-

iscal transplantation and osteotomy, however, remain ofcrucial importance to provide a normalized biomechanical

environment for these new technologies.

Level of evidence Systematic review, Level II.

Keywords Early osteoarthritis ! Knee ! Surgicaltreatment ! Allografts ! Concurrent procedures

Osteochondral allografts

Osteochondral allografts have become an integral part ofarticular cartilage restoration and repair [90]. The use of

osteochondral allografts for the treatment of focal, chon-dral, and osteochondral lesions in the knee is well sup-

ported by clinical experience and peer-reviewed literature

[24, 35]. However, the use of allografts in the treatment ofmore advanced disease, such as that seen in osteoarthritis

(OA), is not as well established [66]. Nonetheless, there is a

need for a biological treatment option for young individ-uals with degenerative conditions of the knee. Fundamen-

tally, biological joint restoration may be appropriate in any

patient considered too young or active for conventionalarthroplasty. While this criterion is often vague, our prac-

tice is to evaluate any patient younger than 50 years for

biological reconstruction.

A. H. Gomoll (&)Cartilage Repair Center, Department of Orthopedic Surgery,Brigham and Women’s Hospital, Boston, MA, USAe-mail: agomoll@yahoo.com

G. Filardo ! S. Zaffagnini ! M. MarcacciBiomechanics Laboratory-III Clinic,Rizzoli Orthopaedic Institute, Bologna, Italy

F. K. Almqvist ! P. Verdonk ! R. VerdonkDepartment of Orthopaedic Surgery and Traumatology,Ghent University Hospital, Ghent, Belgium

W. D. BugbeeScripps Clinic, La Jolla, CA, USA

M. JelicDepartment of Orthopaedic Surgery, Clinical Hospital CenterZagreb, School of Medicine, University of Zagreb,Zagreb, Croatia

J. C. MonllauHospital de la StaCreuI Sant Pau, Universitat Autonomade Barcelona (UAB), Barcelona, Spain

G. PudduClinica Valle Giulia, Rome, Italy

W. G. RodkeySteadman Philippon Research Institute, Vail, CO, USA

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Knee Surg Sports Traumatol Arthrosc (2012) 20:468–486

DOI 10.1007/s00167-011-1714-7

Indications

Common indications for osteochondral allografting arelisted in Table 1. This list defines a broad spectrum of

clinical conditions; however, it is important to note that as

the extent of disease progresses into the realm of OA, theuse of allografts becomes more controversial and the

technical aspects more difficult, often including adjunct

procedures such as osteotomy and ligament reconstructionor meniscal transplant. In treatment of the ‘‘arthritic’’

patient who is considered for biological restoration, the

following diagnostic categories are relevant: osteonecrosisof the femoral condyle, either spontaneous or steroid-

associated; post-traumatic OA, secondary to tibial plateau

fracture malunion, femoral condyle fracture or patellafracture; and cases of unicompartmental OA, either of the

tibiofemoral joint or patellofemoral joint. The latter may be

idiopathic, but in young patients more likely secondary tosome underlying conditions such as a remote meniscec-

tomy or long-standing chondral injury.

Surgical planning

The key equipment issue regarding osteochondral allo-grafting is the availability of the allograft tissue. Osteo-

chondral allografts are size matched to the patient and

obtained from an accredited tissue bank that is experiencedin the recovery, testing, and processing of fresh osteo-

chondral allografts. We prefer fresh as opposed to frozen

allografts in order to maximize chondrocyte viability and,therefore, maintain viable cartilage in the allograft in vivo.

Prior to incision, the surgeon should inspect the allograft to

ensure that it is the appropriate size and anatomic part forthe proposed procedure.

Commercially available instruments can be utilized for

performing large, dowel-type allografts, typically used onthe femoral condyle. However, in larger, degenerative

conditions, the allograft must be often shaped in the free-

hand fashion, utilizing power equipment, such as saws andburs; these grafts are termed ‘‘shell allografts.’’ Therefore,

the surgeon should have the typical instrumentation

utilized for a knee arthroplasty. Fluoroscopy is useful

particularly in tibial plateau allografts or for large femoral

condyle allografts. Fixation of dowel graft is achieved withpress fit with or without the use of bioabsorbable pins or

screws. Small screws, such as cannulated 3.0 or 3.5 screws

should be available to provide fixation for larger shellgrafts.

Surgical technique

The allografting procedure may involve a single surface,such as the femoral condyle or tibial plateau, or a multi-

focal reconstruction such as femoral condyle and trochlea

or both medial and lateral femoral condyles or a so-calledbipolar allograft, which includes resurfacing the tibia and

femoral condyle in a single compartment or the patella and

trochlea. There are technical aspects of each of theseallografts, but they are generally classified into plug or

shell grafts. A plug graft is, essentially, a round graft pre-

pared by commercially available instruments that formgrafts between 15 and 35 mm in diameter. Shell grafts are

more complex geometric shapes that must be prepared by

hand. These are utilized for resurfacing the femoral con-dyle (particularly large or difficult-to-reach areas, such as

the posterior condyle), patella and tibial plateau. Table 2

outlines common diagnoses and allograft patterns.The setup for osteochondral allografting of the knee is

very similar to a unicompartmental arthroplasty. We prefer

the use of regional blocks for postoperative pain manage-ment; however, the anesthesia is at the discretion of the

surgeon and anesthesiologist. A tourniquet is used in all

cases, and the leg positioner is set so the knee can be placedin varying degrees of flexion (70–130"), which is critical

for access to the pathologic lesion(s).

Table 1 Indications for osteochondral allografts in complex kneereconstruction

1. Large, focal chondral defect

2. Osteochondritis dissecans

3. Salvage of previous cartilage surgery

4. Osteonecrosis of the femoral condyle

5. Post-traumatic reconstruction

6. Multifocal chondral disease

7. Unicompartmental arthritis

Table 2 Specific allograft reconstruction options for degenerativeknee conditions

Condition Reconstruction option

1. Spontaneous osteonecrosisof the medial femoralcondyle

Focal allograft, with or withoutHTO

2. Steroid-associatedosteonecrosis

Multiple plugs or shell graft

3. Tibial plateau fracturemalunion

Combined tibial plateau allograftand meniscal transplantation,with or without osteotomy

4. Unicompartmentaltibiofemoral arthrosis(secondary to meniscectomyor repetitive chondral trauma)

Realignment osteotomy,if indicated

Bipolar allograft (tibial plateauwith meniscus and plug or shellfemoral allograft)

5. Patellofemoral arthrosis Bipolar plug or shell allograft, withor without tibial tubercleosteotomy

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The surgical approach for osteochondral allografting

typically utilizes a midline incision and small, retinacularmini-arthrotomy, either medial or lateral to the patella

depending on the compartment. Care should be taken to

protect the meniscus, unless a meniscal transplant isplanned. Once the knee is exposed, the patella must be

mobilized and this can be done by sequentially extending

the arthrotomy proximally as needed. Retractors are placedin the notch (with care taken not to injure the cruciate

ligaments or tibial cartilage), and along the articular marginto expose the knee joint. The knee is then flexed to the

appropriate angle in order to best expose the joint surface

to be grafted.

Femoral condyle plug grafts

Allografts of the femoral condyle can include either mul-

tiple plug grafts or a single shell allograft. In the case of

plug allografts, with the femoral condyle lesion exposed,sizing dowels are used to map out the reconstruction of the

diseased femoral condyle. Often this requires two or even

three grafts, in order to effect a reconstruction of the entirefemoral condyle. Prior to preparing the surface, the surgeon

plans out the size and location of these dowels and begins

in a sequential fashion, either anterior to posterior or pos-terior to anterior. A guide pin is drilled over the sizing

dowel and the lesion is drilled to a depth of 5–7 mm. The

depth of the preparation should be minimal and only deeperthan 5–7 mm in cases of marked bone destruction, such as

seen in osteonecrosis. The guide pin is then removed and

measurements are taken to determine the depth of thepreparation and the first graft is then harvested from the

allograft. The measurements of the recipient site are

transferred to the allograft and excess bone is resected. Thegraft is then lavaged copiously. Once this is done, the graft

is seated into the prepared site and gently seated with either

range of motion (ROM) to utilize joint forces or gentlyimpacted with a tamp. Care should be taken to limit the

applied forces to avoid chondrocyte injury. With the first

graft in place, the second graft is inserted juxtaposed oroverlapping the first graft. If necessary, fixation with either

a bio-absorbable screw or chondral darts can aid in the

fixation. However, care should be taken not to dislodge thefirst graft when preparing for the second graft. The second

graft is placed in a similar fashion, and at this point if the

condyle has been reconstructed, the wound is irrigated anda routine closure over a drain is performed.

Femoral condyle shell grafts

In cases where utilizing multiple dowel grafts is not

appropriate or technically impossible (i.e., in the posteriorfemoral condyle), a shell graft is created. This is done

utilizing a saw or bur to create a flat surface, very similar to

either a posterior or a distal cut performed during a kneearthroplasty. However, this is performed using a freehand

technique, and once the cut is made, the prepared surface is

then measured in length and width. These measurementsare transferred to the allograft and after marking the donor

condyle, an appropriately sized graft is cut freehand. A

series of preliminary fittings are performed with furthertrimming of the graft as necessary. It is important in this

setting to not only reconstruct both the length and width,but also the femoral condyle height. This may require

fluoroscopic imaging. With minimal fixation, a ROM can

be performed to confirm that the graft is not overstuffingthe compartment and that it is relatively stable prior to

fixation. Because these are uncontained grafts, they require

more fixation, and typically bio-absorbable or 3.0 cannu-lated screws can be used from an extra-articular position to

avoid potentially prominent hardware damaging the

opposing articular surface.

Tibial plateau allografts

Tibial plateau allografts are particularly useful for recon-

struction of post-traumatic problems, such as tibial plateau

fractures. In this setting, the procedure is very similar toresurfacing of the tibial plateau in unicompartmental

arthroplasty. After exposing the knee, it must be deter-

mined whether the meniscus should be replaced. Mostoften, we replace the meniscus with the tibial plateau graft

because meniscus pathology is almost universal in cases of

post-traumatic or degenerative OA. After excising themeniscus remnant and determining the amount of bone loss

from the involved plateau, the reciprocating saw is used to

make a vertical cut and then either using a unicompart-mental knee jig or a freehand technique, a limited resection

of the tibial plateau is made. This is an important point,

because frequently bone loss had led to a loss of plateauheight and this will be restored with the allograft. Over-

resection of the tibial plateau should be avoided.

Once the resection is made and the meniscal remnant isremoved, the knee is brought into extension and the gap

between femoral condyle and the resected tibial surface is

measured. This gives the surgeon a preliminary measure-ment of the thickness of the tibial plateau graft that needs

to be prepared. The length and width of the prepared tibial

surface also should be measured and any bone defectsshould be curetted and grafted. The length, width and

thickness measurements obtained are then transferred to

the tibial plateau allograft. The graft is harvested takingcare to include the meniscus attachments with the graft.

The graft is then measured and re-cut as necessary. The

meniscus is then seated under the femoral condyle withgreat care, and ROM is utilized to determine the balancing

470 Knee Surg Sports Traumatol Arthrosc (2012) 20:468–486

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of the involved compartment. Fluoroscopic images should

also be obtained to ensure that the tibial plateau height andvarus/valgus angulation have been restored. Typically,

multiple small revisions of the graft or the recipient plateau

are performed in order to obtain an excellent fit with theappropriate kinematics. Once this is accomplished, typi-

cally screw fixation is used from the anterior and mid-

coronal line to fix the graft to the tibial plateau andmeniscus repair is performed in standard fashion.

Bipolar grafts

Single-compartment, reciprocal bipolar grafts are techni-cally very challenging and should be used with great care.

This is typically the case with unicompartmental OA or

when both femoral and tibial surfaces are diseased (Fig. 1).The technical aspects of each allograft have been outlined

above. The sequence of events would be resection of the

tibial surface, which will allow more access to the femoralside, preliminary preparation of the tibial graft, and allo-

grafting of the femoral condyle followed by insertion of

tibial allograft (Fig. 2).

Rehabilitation guidelines

Patients are kept on touch-down weight-bearing restrictions

for 8–12 weeks, depending on the size of the transplant.

ROM is typically unrestricted and the use of continuouspassive motion (CPM) is optional unless there are concerns

for the development of stiffness.

Complications

Complications include general surgical complicationsincluding infection, neurovascular damage, and DVT, as

well as those specific to osteochondral allografts, including

disease transmission (HIV, hepatitis), failure to incorpo-rate, and graft collapse.

Results

The results of osteochondral allografting for OA conditions

of the knee are difficult to summarize. Gross et al. havereported 75% 10-year survivorship of tibial grafts in the

management of post-traumatic OA [32, 91, 98] and up to

75% good to excellent outcomes using allografts for pa-tellofemoral disease. Gortz et al. [37] reported 90% graft

survival rate at 6 years in steroid-induced osteonecrosis of

the femoral condyles. The outcome of bipolar tibiofemoraldisease, in patients attempting to defer arthroplasty, shows

high patient satisfaction but a 60% reoperation rate and

30% rate of conversion to TKA at average of 6 years [36].

Allogenic cartilage grafts

Different from traditional osteochondral allografts, allo-

genic cartilage grafts consist of the cartilage phase only,

without attached bone. Therefore, they should be seen as acell carrier, rather than structural graft. Chondrocytes

appear to be immune-privileged since they lack certain

proteins associated with allo-reactivity, while expressingothers that have been shown to suppress lymphocyte pro-

liferation [43].

Two distinct subsets of this technology exist: morcel-lized cartilage allograft and allogenic chondrocyte

implants: the former is currently available in the UnitedStates under the name DeNovo NT (Zimmer, Warshaw,

Indiana). It consists of small (approximately 1 mm3) cubes

of hyaline cartilage obtained from juvenile donor, resultingin a chondrocyte density 100-fold higher than that of adult

cartilage. Basic science studies have demonstrated that the

donor chondrocytes have the capability to leave the

Fig. 1 Unicompartmental degeneration

Fig. 2 Bipolar grafts

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cartilage cubes and produce matrix, eventually filling the

defect [29]. Allogenic chondrocyte implants are producedfrom fresh osteochondral grafts. The cartilage is harvested

and digested to release the cells contained within. The

chondrocytes are isolated [31, 49] and mixed with alginateto form beads that are implanted into the cartilage defect

[34].

Genetic factors are suspected in many cases of early OAthat cannot be explained otherwise due to malalignment,

meniscal and ligamentous insufficiency, or trauma. The useof an allogenic, rather than autologous, cell source offers the

potential to avoid the patient’s own, potentially compro-

mised chondrocytes, making this technology an intriguingoption for cartilage repair.

Indications

The indications follow those of other cell-based proce-

dures, such as autologous chondrocyte implantation (ACI).

Surgical planning

The main concern is the availability of adequate tissue to

implant. A thorough preoperative workup including MRI

and/or arthroscopy is therefore crucial to establish lesionnumber and size.

Surgical technique

The defect is accessed through the appropriate approach,

mostly mini-arthrotomies. The defect is then preparedaccording to microfracture/ACI principles, including the

creation of vertical shoulders, removal of the calcified

layer, and preservation of the subchondral plate withoutundue bleeding.

For the particulated cartilage graft, the defect is tem-

plated using aluminum foil (e.g., suture packaging). Thetemplate should have a rim to facilitate the creation of the

implant. Cartilage cubes are then placed into the template

and fibrin glue is added to form a gel-like implant. Afterallowing a few minutes for hardening, the implant is

transferred into the defect and secured with additional

fibrin glue. Alternatively, the cartilage cubes can be placeddirectly into the defect with forceps and then covered with

fibrin glue in situ (Fig. 3). A covering patch is only

required in cases that are concerning for implant dis-placement, for example in larger or bipolar defects, espe-

cially with compromised shoulders.

For the allogenic chondrocyte implant, a periostealpatch is sutured onto the defect, with the cambium layer

facing the defect. A small opening is left for implantation

of the alginate beads, which are then inserted manually

(Fig. 4). Subsequently, the opening is sutured and sealed

with fibrin glue.

Rehabilitation guidelines

The postoperative guidelines mirror those of other cell-

based therapies, consisting of weight-bearing restrictions

and gradual increase in ROM depending on the defectlocation.

Complications

Adverse events are similar to those of other cell-basedtherapies. The use of donor tissue introduces the risk of

disease transmission, which necessitates strict donor

screening.

Fig. 3 Patellar defect filled with particulated cartilage allograft,secured with fibrin glue

Fig. 4 The alginate beads are inserted into the defect

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Results

Due to the relatively recent introduction of DeNovo NTinto clinical practice, only a case report and an abstract

have been published. In the latter, Farr et al. [26] reported

on 7 patients with more than 1-year follow-up afterimplantation with juvenile cartilage allograft. Patients

improved over baseline; however, at this early time-point,

only few of the parameters showed statistically significantincreases.

Almqvist et al. [1] report on 21 consecutive patients (13

men and 8 women) followed for 36 months after allogenicchondrocyte implantation. The mean age of the patients

was 33 years (range, 12–47 years). The mean duration of

symptoms before surgery was 33.2 months (range,6–73 months). All lesions were focal: 15 on the medial

femoral condyle, 4 on the lateral femoral condyle, 1 on the

patella, and 1 on the trochlea. All lesions were InternationalCartilage Repair Society (ICRS) grade III–IV with a mean

size of 2.6 cm2 (range, 1–9.25 cm2). The cause of injury

was traumatic in 12 cases and focal nontraumatic (focalOA, osteochondral lesions) in 9 cases. During the follow-

up period, the VAS pain and WOMAC scores improved

significantly from baseline to postoperative.

Meniscal scaffolds and allograft transplantation

Degenerative meniscal lesions and pathological changes in

the menisci are natural consequences of meniscal tissueaging and are accelerated by joint overuse. Degenerative

meniscal lesions are more frequent in men than women

(2–1), which is exactly the opposite of OA and thus sup-ports the concept of primary degenerative meniscal lesions.

Degenerative lesions predominantly occur in the fourth or

fifth decade of life, but may also develop earlier, even inyoung athletes [4, 5].

The treatment may include meniscal resection but also

meniscal replacement using implants. Meniscal transplan-tation can be considered in case of massive/total meniscal

resection. Meniscal replacement using scaffolds and men-

iscal allografts after partial and total meniscectomy,respectively, provides an important treatment option. Both

approaches have distinct indications [12, 58, 78–83, 109,

114–116].

Meniscal scaffolds

Indications

Specific indications and contraindications have beendeveloped for meniscal scaffolds [12, 58, 78–83, 108, 109,

114–116], mainly a history of meniscal injury with loss of

[25% of meniscal tissue due to trauma or surgical inter-

vention in patients with no or minimal chondral damage(Kellgren–Lawrence grade 1/2, Outbridge 1/2).

Contraindications Scaffolds require some residual men-

iscal tissue for attachment and are therefore contraindicatedin meniscectomized patients without anterior/posterior

horn attachments and a circumferential rim. Additionally,

ligament, cartilage, or alignment abnormalities should becorrected in a staged or concurrent fashion. Any potential

allergy to the scaffold materials should be carefully ruledout.

Surgical planning

Surgical planning includes preoperative confirmation that

meniscal tissue remains, since current scaffolds are notindicated for the treatment of completely meniscectomized

patients. The joint should also be evaluated for other

pathologies, such as cartilage or ligament damage thatcould be treated concurrently.

Surgical technique

Both Menaflex [58, 78, 83, 114] (ReGen Biologics, USA)

and Actifit [109] (Orteq, UK) have comparable surgicalimplantation techniques.

Preparation of implant bed Preparation of the implant

site results in a full-thickness meniscus defect (i.e., noresidual flaps, loose or degenerative tissue). The remaining

meniscus rim should be intact over the entire length. The

prepared defect site should maintain a uniform width of themeniscus rim and extend into either the red/white or red/

red zone of the meniscus (Fig. 5). In cases where the rim

extends out to the red/white zone, puncture holes are madein the rim using a soft tissue microfracture awl or similar

instrument to extend the blood supply. The anterior and

posterior attachment points are trimmed square to acceptthe implant.

Measurement of defect size After implant site prepara-

tion, the defect is measured with the specifically designedmeasuring device. Since the implant is designed with fixed

widths and curvatures, the arc length of the defect site is

needed to size the implant properly. Measurements aretaken using the measuring rod that is loaded into the can-

nula and started at the posterior aspect of the lesion and

continued until the correct arc length is noted (Fig. 6).

Suturing the implant to the remaining meniscus With the

implant positioned properly, it is fixed to the host meniscus

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rim using standard inside-out meniscal repair techniques.Alternatively, an all-inside approach can be utilized, which

can be more time-efficient and potentially minimize risks

inherently associated with an inside-out suture procedure.The implant is sized 10% larger than the measured defect

and is inserted into the joint through an enlarged medial

portal using a curved atraumatic vascular clamp (14- to16-cm-long Cooley clamp). The all-inside suture system is

used to fix the implant with horizontal and vertical mattress

sutures. It is recommended to first place a horizontal sutureat the posterior junction, then the vertical sutures working

anteriorly, and finally another horizontal suture at the

anterior junction. When using the all-inside suture tech-nique, the portals are placed low and adjacent to the medial

and lateral margins of the patellar tendon. An accessory

portal 2–3 cm lateral to the lateral portal facilitates place-ment of the most anterior all-inside suture, especially when

the lesion and implant extend to the anterior third of the

meniscus; otherwise, an outside-in suturing technique canbe utilized.

Rehabilitation guidelines

Rehabilitation [78, 83, 116] includes early protection of the

implant with limited weight-bearing and motion during thefirst 6–8 weeks. Return to full and unrestricted activities is

not recommended until 6 months postoperatively.

Complications

No specific complications inherent to the scaffolds have

been described. General complications are similar to those

of meniscal repair and transplantation.

Results of Menaflex implantation

Rodkey et al. [79–83] recently reported a 5-year follow-up

study on Menaflex. Three hundred and eleven patients with

an irreparable medial meniscus injury (acute group) or aprevious partial medial meniscectomy (PMM) (chronic

group) were randomized to PMM versus Menaflex

implantation. Menaflex patients undergoing second-lookarthroscopy at 1 year demonstrated significantly increased

meniscus tissue. Chronic patients receiving an implant

regained significantly more of their lost activity than didcontrols and underwent significantly fewer non-protocol

reoperations over 5 years. No differences were detected

between the two treatment groups in acute patients.Monllau et al. [58] evaluated clinical, functional, and

MRI outcomes of 22 Menaflex patients after a minimum

of 10 years postoperatively. The mean Lysholm scoreimproved from 59.9 preoperatively to 89.6 at 1 year and

87.5 at final follow-up. The results were good or

excellent in 83%; satisfaction with the procedure was 3.4of 4 points and the mean VAS pain score improved by

3.5 points. Radiographic evaluation showed either mini-

mal or no narrowing of the joint line. MRI was read asnearly normal in 64% of cases and normal in 21%.

There were two failures but no complications related to

the device.Zaffagnini et al. [116] reported 10-year follow-up in 33

male patients after either Menaflex or PMM alone based on

patient choice. The Menaflex group showed significantlylower pain and higher objective IKDC, Tegner index, and

SF-36 scores; no significant differences between groups

were reported regarding the Lysholm score. Radiographicevaluation showed significantly less medial joint space

narrowing in Menaflex patients, and MRI scores remained

constant between 5 and 10 years after surgery.

Fig. 5 Upon completion of the meniscectomy, the defect site shouldhave a uniform width of the meniscus rim extending into the red/white or red/red zones. When the defect site is prepared to accept thescaffold, the anterior and posterior attachment points should betrimmed square to accept the implant

Fig. 6 A flexible measuring device is used to measure the arc lengthof the defect in order to size the meniscus implant properly

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Results of Actifit implantation

Verdonk et al. reported on 52 patients after Actifitimplantation; preliminary 12-month efficacy data were

available for 46 patients and full safety data available for

all 52 patients [109, 110]. Thirty-four received a medialmeniscal implant and 18 received a lateral implant. The

longitudinal length of the meniscus defects ranged from 30

to 70 mm. The majority of adverse events were mild ormoderate; specifically, no inflammatory reaction to the

scaffold implant was observed during gross examination at

12 months. At 3 months postimplantation, early evidenceof tissue ingrowth in the peripheral half of the scaffold was

observed on MRI in 86% of patients. MRI findings at

12 months postimplantation showed stable or improvedcartilage scores in the index compartment compared to

baseline. No evidence of necrosis or cell death, but

meniscus-like cells visible in distinct layers, was observedin all biopsies taken at the 1-year second-look arthroscopy.

Statistically significant improvements were reported for

IKDC functionality, Lysholm, VAS knee pain, and KOOSsubscales at 6, 12, and 24 months postimplantation.

Meniscal allograft transplantation

Indications

According to current recommendations, meniscal allograft

transplantation is indicated in three specific clinical

settings:

1. Young patients with a history of meniscectomy who

have pain localized to the meniscus-deficient compart-ment, particularly after lateral meniscectomy.

2. ACL-deficient patients who have had previous medial

meniscectomy with concomitant ACL reconstructionand who might benefit from the increased stability

afforded by a functional medial meniscus.

3. In an effort to avert early joint degeneration, some alsoconsider young, athletic patients who have had total

meniscectomy as candidates for meniscal transplanta-

tion prior to symptom onset. However, the resultsobtained so far still preclude a return to high-impact

sports.

Contraindications include advanced chondral degenera-

tion, although some studies suggest that cartilage degen-

eration is not a significant risk factor for failure. In general,cartilage lesions greater than ICRS grade III articular

should be small and localized and may be treated con-

comitantly. Radiographic evidence of significant osteo-phyte formation or femoral condyle flattening is associated

with inferior postoperative results because these structural

modifications alter the morphology of the femoral condyle.

Other contraindications to meniscal transplantation are

obesity, skeletal immaturity, instability of the knee joint(which may be addressed in conjunction with transplanta-

tion), synovial disease, inflammatory arthritis and previous

joint infection and obvious squaring of the femoral condyle[7, 13, 16, 17, 44, 60, 74, 77, 85, 100, 105, 106, 112].

Surgical planning

Meniscal allografts are matched side- and size specificbased on preoperative radiographs with correction for

magnification [70]. Size and position of the transplant are

critical, and as small as a 10% size mismatch has beenfound to have major effects. Furthermore, even when

properly sized, biomechanical studies have demonstrated a

failure to establish normal contact stresses with nonana-tomical graft placement [47, 117].

Surgical technique

There are several techniques available for meniscal trans-

plantation: originally performed as open surgery, technicaldevelopments have allowed arthroscopic implantation

using soft tissue or bone block fixation.

Open technique The allograft, either frozen or viable, isprepared with 2-0 sutures placed every 5 mm along the

meniscal rim. In a medial approach, a paramedial parapa-

tellar incision is made proceeding toward bone flakeremoval of the medial collateral ligament insertion of the

femur. This release/osteotomy allows for widening the

medial compartment. After freshening up the remnantmeniscal wall, the allograft is sutured in place. Refixation

of the MCL is done using a staple.

A lateral parapatellar approach allows for lateral meni-scal transplantation. An osteotomy of the lateral collateral

ligament and popliteus insertion on the femoral condyle

allows for opening up the lateral compartment. This allowsfor easy insertion of the lateral meniscal transplant along

the meniscal wall starting from the posterior horn on.

Refixation is done using a cancellous screw allowingfor immediate rehabilitation.

Arthroscopic technique The arthroscopic approach

allows the surgeon not to interfere with the collateral lig-ament physiology and stability. It also allows improved

anatomic positioning of the implant with tunnel fixation

through the original anterior and posterior meniscal rootattachment sites.

After arthroscopic evaluation of the appropriate meni-

scal wall, the tissues are freshened up to improve periph-eral ingrowth. Bone tunnels are created in the anterior and

posterior horn attachment sites, allowing for secure fixation

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over a bone-bridge on the anteromedial aspect of the tibia.

Thereafter the implant is pulled to its anatomic positionthrough an arthroscopic-assisted opening. Fixation is per-

formed using an all-inside or inside-out fixation [6].

Rehabilitation guidelines

Rehabilitation is initially focused on restoring mobility tothe joint without endangering ingrowth and healing of the

graft. Therefore, 3 weeks of non-weight-bearing are pre-scribed, followed by 3 weeks of partial weight-bearing

(50% of body weight). Progression to full weight-bearing is

allowed from week 6 to 10 postoperatively. The use of aknee brace is not strictly necessary and depends on the

morphology and profile of the patient. ROM is limited to

0–30" during the first 2 weeks and increased by 30" every2 weeks. Isometric muscle strengthening and co-contrac-

tion exercises are prescribed from postoperative day 1.

Straight leg raise, however, is prohibited during the first3 weeks. Proprioceptive training is started after week 3.

Swimming is allowed after week 6 and biking after week

12. Running is progressively introduced from week 20[104].

Complications

Meniscal transplantation has the general risks associated

with meniscal repair, and additional risks specific to thetransplant itself, such as disease transmission from the

donor and injury to the patellar tendon due to the anterior

approach.

Results

Biomechanical studies have demonstrated the ability of

meniscal transplantation to decrease the stresses in a

compartment with meniscal loss [65, 111]. There is alsoample clinical evidence to support meniscus allograft

transplantation in meniscectomized painful knees, with

observance of the proper indications [13, 18, 30, 42, 55, 62,77, 89, 107]. Significant relief of pain and improvement in

function have been achieved in a high percentage of

patients. These improvements appear to be long-lasting in70% of patients. Based on plain radiology and MRI, a

subset of patients does not show further cartilage degen-

eration, indicating a potential chondroprotective effect, assuggested by both preclinical animal studies [101] and

long-term clinical follow-up [107]. Cartilage damage was

historically seen as an at least relative, if not absolute,contraindication for meniscal transplantation due to the

increased failure rate [30, 85]. The proven deleterious

effects of meniscal loss and positive outcomes seen withmeniscal transplantation provide a strong rationale for

adding meniscal transplantation to cartilage repair proce-

dures in patients with an absent meniscus. Two separatestudies have demonstrated the safety, feasibility, and effi-

cacy of concomitant procedures [27, 84]. While the lack of

a conservatively treated control group makes it difficult toestablish the true chondroprotective effect of meniscal

replacement for the meniscectomized painful knee, it

should no longer be considered experimental given theextensive results published in the literature.

Osteotomy

Tibial tubercle osteotomy for patellofemoral cartilage

disease

Patellar maltracking has been recognized as a crucial

component of patellofemoral (PF) cartilage disease, and its

correction is an important adjunct to cartilage repair in thislocation. For example, early results of ACI in the PF

compartment were disappointing, with less than 30% good

or excellent results [9]. However, with increased recogni-tion and correction of patellar maltracking, the outcomes

have improved drastically, recent studies reporting suc-

cessful outcomes in over 80% of patients [25, 39, 57, 67].Several factors are involved in patellar maltracking,

including soft tissue imbalance with often tight lateral and

loose medial structures; bony malalignment plays animportant role, including rotational deformities of the

proximal femur and tibia, as well as the more commonly

seen increased lateral displacement of the tibial tubercle.Rebalancing of patellar maltracking involves correction

of all abnormalities through soft tissue releases and im-

brications, as well as tibial tubercle osteotomy (TTO) inpatients with abnormal tibial tubercle to trochlear groove

distance (TT–TG; normal\ 15 mm; abnormal[ 20 mm)

[3, 21]. This distance is calculated by measuring themedial-to-lateral distance between the center of the tibial

tubercle and the center of the trochlear grove, utilizing

axial imaging such as MRI or CT. The goal of a TTO is thenormalization of the TT–TG distance and improved joint

congruency with redistribution of stresses from the lateral

to the medial facet. The currently favored type of TTOcombines normalization of the TT–TG distance through

medialization with a generalized unloading of the PF

compartment through anteriorization [15]. This osteotomywas popularized by Fulkerson and is named anteromedi-

alization (AMZ) [5, 71, 86].

Indications

TTO is indicated in patients with PF cartilage disease,predominately in the lateral patellar facet. Medial or

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pan-patellar defects, especially when combined with a cen-

tral or medial trochlear defect, present a relative contrain-dication for TTO unless combined with cartilage repair.

Surgical planning

Preoperative planning includes standard radiographs of the

knee, including patellar views to evaluate for joint spacenarrowing, patellar tilt, and subluxation. Lateral views are

valuable to determine patellar height and rule out trochleardysplasia. MRI is helpful to evaluate the medial patel-

lofemoral ligament (MPFL) and morphology of the troch-

lear groove and calculate the TT–TG distance. Generallyspeaking, treatment of chondrosis of the patellofemoral

joint through TTO includes both anteriorization and med-

ialization. The goal is to decrease PF load through anteri-orization of approximately 1 cm, while correcting the TT–

TG distance to normal (\15 mm). TTO in the setting of a

near-normal TT–TG distance should be performed with asteeper angle, while a very abnormal TT–TG distance

might require a flatter osteotomy to effect more medial-

ization than anteriorization (Fig. 7).Lateral patellar facet chondrosis can be effectively

addressed through isolated TTO (unless in the very young

patient who should also undergo cartilage repair), whilepan-patellar or medial defects have had less success with

isolated TTO and therefore should be considered for con-

current cartilage repair.

Surgical technique

A midline incision usually provides the most versatile

approach. The medial and lateral aspect of the patellar

tendon is dissected free and a retractor is placed behind thepatellar tendon. The musculature of the anterior compart-

ment is elevated from the lateral wall of the tibia in a sub-

periosteal fashion and another retractor is placed to protectthe musculature and neurovascular structures. Freehand or

using a cutting guide, the tibial tubercle osteotomy is now

performed with the oscillating saw under constant irriga-tion, frequently leaving a distal hinge. The fragment is

mobilized and moved anteromedially by the previously

calculated distance, then held in place with large reductionforceps. ROM of the knee allows assessment of patellar

tracking, and the tubercle position can be adjusted as

needed. In patients with a tight lateral retinaculum, aselective lateral release or lateral lengthening should be

performed to avoid lateral overload or persistent lateral

maltracking. Once the tibial tubercle position is optimized,the fragment is secured, commonly with 2 bicortical 4.5-

mm lag screws. Bone graft can be applied around the

osteotomy site.

Rehabilitation guidelines

Patients are kept touch-down weight-bearing on crutches

for 6 weeks to minimize the risk of tibia fracture untilthe osteotomy is healed. ROM is not restricted; however,

straight leg raises should be avoided until healing of the

osteotomy. Quadriceps isometrics and electrical stimula-tion is helpful in the immediate postoperative period.

The use of a CPM is optional, but patellar mobilizationand ROM exercises are important to reduce the risk of

stiffness.

Complications

Risks include damage to the posterior neurovascular bun-dle from screws placed straight anteroposterior, as well as

damage to the anterior tibial vessels with dissection deep in

the anterior compartment. The patellar tendon should beprotected during the osteotomy to avoid injury from the

saw or osteotome. Other risks include compartment syn-

drome, nonunion, and iatrogenic medial patellar instabilitywith overmedialization.

Results

Isolated AMZ tibial tubercle osteotomy has demonstrated

clinical outcomes closely related to the location ofchondrosis on the patella: good and excellent (G/E)

Fig. 7 Axial CT image demonstrating different osteotomy angles: 0"(flat) cut achieves pure medialization for the treatment of patellarinstability without chondrosis. The 45" oblique cut is the classicanteromedialization TTO as popularized by Fulkerson; 60" and 80"cuts are modifications that provide more anteriorization than medi-alization for patients with normal TT–TG distance and in those withmedial chondrosis treated with concurrent cartilage repair

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outcomes were reported in 87% of patients with chondral

defects of the inferior (type-1) or lateral (type-2) patella.Since AMZ TTO increases load on the medial and

proximal patella, it has demonstrated poor outcomes with

medial (type-3; G/E in 55%), proximal, or diffuse (type-4; G/E in 20%) defects. When patellar defects were seen

in combination with a central trochlear defect, all

patients reported poor outcomes [68]. Henderson [39]investigated the role of TTO in patellar cartilage repair

with ACI, comparing two groups of patients with patellarACI: one group with normal patellar tracking undergoing

isolated ACI and another group of patients with patellar

maltracking that underwent combined ACI and TTO.Those patients with concomitant TTO experienced

greater improvement in function at 2 years.

Tibial and femoral osteotomy for lower extremity

malalignment

Osteotomy is one of the oldest surgical techniques and

remains an important procedure for active, physiologically

young patients with symptomatic unicompartmental OAand malalignment. Among other factors, early and

aggressive treatment of meniscal tears, as well as the

increased incidence of sports-related ligament injuries,such as ACL tears, has led to an increased incidence of OA

in younger age groups. Coupled with the desire to stay

active until later in life, this has resulted in increasingnumbers of patients presenting with early knee OA wishing

to avoid arthroplasty.

Different from arthroplasty, osteotomy does not requirepermanent activity restriction. It has also become an

important adjunct to cartilage repair and other soft tissue

procedures, such as meniscus transplantation and ligamentreconstruction [53, 113]. Biomechanically, unicompart-

mental OA is caused by local overload exceeding the

resilience of the osteochondral unit, resulting in acceleratedtissue degeneration. The rationale for osteotomy is to

correct the malalignment, thereby decreasing and redis-

tributing excessive forces.

Indications

The main indications for osteotomy are malalignmentassociated with unicompartmental OA, cartilage or meni-

scal lesions, and ligament instability [2, 59, 61, 113].

Generalized OA affecting multiple compartments is acontraindication for osteotomy and should be considered

for arthroplasty. However, mild patellofemoral OA appears

to not significantly affect the outcomes of osteotomy [46,52]. In general, preoperative MRI should be strongly

considered to assess the articular surface and meniscus of

the contralateral compartment. Additional contraindica-tions include meniscal deficiency in the contralateral

compartment even with intact articular cartilage, inflam-

matory disease, decreased motion with less than 90 degreesof flexion or more than 15 degrees of flexion contracture,

tibial subluxation greater than 1 cm, obesity, smoking and

compromised bone stock [8, 56, 63, 96, 97, 113].

Surgical planning

Choice of osteotomy: opening versus closing wedge Both

opening- and closing-wedge osteotomies are available to

address malalignment (Fig. 8a–d): a medial opening-wedge high tibial osteotomy (HTO) is usually performed

when a severe varus deformity is present with proximal

tibial malrotation, as is often seen in patients with idio-pathic (opposed to acquired) varus morphotype. We also

use this type of osteotomy when we need to correct tibial

slope in case of associated ligament laxity. A lateral clos-ing-wedge HTO in our experience is performed for OA

patients with no morphotype alterations and with light or

moderate deformity. However, it is more difficult to changethe tibial slope. Additional factors that influence the choice

of osteotomy include age, bone and tissue quality, patellar

height, functional demand, limb length, previous incisions,and psychological aspects. Patients at risk for nonunion,

such as heavy patients or smokers, should be strongly

considered for closing-wedge osteotomy, if they are sur-gical candidates at all.

Fig. 8 a Medial opening-wedge HTO. b Lateral opening-wedge DFO. c Lateral closing-wedge HTO. d Medial closing-wedge DFO

478 Knee Surg Sports Traumatol Arthrosc (2012) 20:468–486

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The advantages of medial opening-wedge HTO include

preservation of the tibiofibular joint, no risk of injury to theperoneal nerve, no loosening of posterolateral structures,

no limb shortening and easier adjustment of the tibial

slope. The disadvantages are the potential for loss of cor-rection, longer rehabilitation, the risk of nonunion, and the

need for bone grafting. Moreover, there is a greater inci-

dence of patella baja and increased posterior tibial slope.Lateral closing-wedge HTO does not require bone

grafting, allows earlier weight-bearing, has less risk ofnonunion, and loss of correction. However, closing-wedge

osteotomy alters the tibial shape, which can complicate

subsequent arthroplasty. Moreover, the need for fibularosteotomy increases the risk of nonunions and peroneal

nerve palsy.

Isolated lateral compartment OA is much less commonthan medial and can be treated in either the proximal tibia

or, more commonly, the distal femur. Correction on the

tibial side has been criticized because a varus-producingHTO can produce an obliquity of the joint line, which is

rare with correction on the femoral side. However, a varus-

producing HTO unloads the lateral compartment in bothflexion and extension, whereas a distal femoral osteotomy

(DFO) is biomechanically effective only in extension [14,

38, 54].

Planning of correction angle Standard evaluation

includes bilateral weight-bearing anteroposterior radio-

graphs in full extension and posteroanterior views in 45" offlexion (Rosenberg view), lateral and skyline views. The

Rosenberg view is of particular value when the deformity

is associated with lateral compartment OA and with cru-ciate insufficiency—due to the anterior tibial subluxation,

the chondral wear is located predominately in the posterior

medial tibial plateau. MRI is useful to investigate chondraland meniscal damage as well as subchondral edema. Most

importantly, a bilateral full-length alignment radiograph is

requested with double-leg standing, and with single-legstanding in case of associated knee laxity with a varus

thrust. Several measurements are taken for preoperative

planning, specifically the weight-bearing axis that connectsthe centers of the femoral head and talus. Lateral radio-

graphs are assessed for sagittal plane deformity, including

measurement of posterior tibial slope.The valgus-producing HTO is planned according to the

method described by Dugdale et al. [22]. For medial

compartment OA, the weight-bearing line must be movedto 62% across the width of the tibial plateau from medial to

lateral. In case of knee laxity, excess deformity from the

lateral soft tissue laxity is accounted for by subtractingthe increase in congruency angle when compared with the

unaffected leg on the single-leg standing film. By mea-

suring the width of the tibia at the level of the proposed

osteotomy, the surgeon can convert the required angular

correction into a wedge size [69]. In the ACL-deficientknee, the osteotomy is also planned to decrease the pos-

terior tibial slope, which reduces strain on the ACL. Con-

versely, in the PCL-deficient knee, the tibial slope must beincreased in order to produce anterior tibial translation and

decrease stress on the PCL.

Extensive experience has shown that in the varus kneewith OA, overcorrection is absolutely essential to optimize

the long-term outcomes [19, 40]. However, in varus kneepatients without OA but rather laxity or focal cartilage

defects, only correction to neutral (rather than valgus)

alignment should be obtained to avoid overloading thelateral compartment.

For the varus-producing osteotomies, we aim to move

the mechanical axis to a point 48–50% across the width ofthe tibial plateau from lateral to medial [72], mostly by

means of a DFO and only in select cases by a medial

closing-wedge HTO. In the valgus knee, the joint line has avalgus tilt with obliquity from superolateral to inferome-

dial. A medial closing-wedge HTO, especially in patients

with valgus deformities exceeding 10", further increasesjoint line obliquity with concomitant increases in shear

forces and lateral subluxation during gait. Extensive clin-

ical experience has shown that overcorrection in the valgusknee is absolutely contraindicated if one wants to optimize

long-term results from a varus-producing osteotomy [72].

Surgical technique

Medial opening-wedge HTO Surgery is performed withthe patient supine on the operating table, with a sandbag

beneath the trochanteric region to place the extremity in

neutral rotation. A radiolucent table is used to allow fluo-roscopic visualization of hip, knee, and ankle joints for

intraoperative assessment of alignment. Standard draping is

performed, including the iliac crest if bone graft is to beharvested from here. The tourniquet is inflated and an

arthroscopy is performed to assess the relative integrity of

the lateral and patellofemoral compartments and to treatany intraarticular pathology such as a meniscal tear or anvil

osteophyte that can prevent knee extension. The antero-

medial aspect of the tibia is then exposed through a verticalskin incision centered between the medial border of the

anterior tibial tubercle and the anterior edge of the medial

collateral ligament and extending 6–8 cm distally to thejoint line. Sharp dissection is carried out and the hamstring

tendons are identified and divided leaving 1 cm of the

tendon insertion on the tibia. The underlying superficialMCL is cut horizontally, without risk of instability because

the deep, and much more stabilizing, MCL remains intact.

A retractor is placed behind the tibial metaphysis to protectthe neurovascular bundle, and a second retractor is placed

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under the patellar tendon. With the knee in extension and

under fluoroscopic control, a guide wire is drilled throughthe proximal tibia from medial to lateral. This is obliquely

oriented starting medially approximately 4 cm distally to

the joint line and is directed across the superior edge of thetibial tubercle to a point 1 cm below the joint line in the

direction of the tip of the head of the fibula. The osteotomy

is then performed keeping the oscillating saw blade belowand parallel to the guide wire in order to prevent proximal

migration of the osteotomy into the joint. The saw is usedto cut the medial cortex only, then a sharp osteotome is

used to complete the osteotomy, making certain that the

cancellous metaphysis and especially the anterior and theposterior cortices are completely disrupted, while pre-

serving a lateral hinge of approximately 1 cm of intact

bone. While performing the osteotomy, it is important toregularly check progress with the fluoroscope to ensure the

appropriate depth and direction of the cut. The osteotomy

is now opened; an appropriate plate is selected and placed.Current osteotomy systems generally utilize locking plate

designs, which provide more stability and decrease the risk

of loss of correction and nonunion. Before securing theplate, alignment is checked with fluoroscopy utilizing a

guide rod or Bovie cord from the center of the femoral head

through the knee to the center of the talus. The osteotomygap is adjusted as needed to achieve the desired alignment;

then, the plate is secured in place with the appropriate

screws. The defect can be left open if less than 7.5 mm, orfilled using the preferred bone graft or bone substitute. For

larger corrections, we prefer to use two corticocancellous

iliac crest wedges, one anterior and one posterior to theplate. Final fluoroscopic assessment ensures adequate plate

position (Fig. 9). A suction drain is placed and closure is

completed in layers with repair of the hamstrings tendons[28].

Lateral opening-wedge DFO An identical setup is used

as for HTO. The lateral aspect of the femur is approachedthrough a standard straight incision through the skin and

the fascia starting 2 fingers breadth distally to the epicon-

dyle and extending the incision about 12 cm proximally.The approach is carried down to the vastus lateralis, which

is dissected from the intermuscular septum, and perforating

vessels are carefully controlled with ligature or electro-cautery. The muscle is retracted anteriorly, exposing the

lateral cortex. The procedure is facilitated by flexion of the

knee. The guide pin is placed in a slightly oblique direction(about 20"), starting from a proximal point 3 fingers

breadth above the lateral epicondyle (safely proximal to the

trochlear groove), and aiming for the medial metaphysealflare. A second retractor is placed posteriorly to avoid

neurovascular damage, and the osteotomy is started with

the saw cutting just the cortical bone. It is very important to

start the osteotomy with the saw and then continue with theosteotome parallel and proximal to the guide pin to prevent

intraarticular fracture. A medial hinge is again preserved.

The osteotomy must be perpendicular to the long axis ofthe femur to have the plate well oriented with the femoral

shaft. The osteotomy is distracted and the appropriate plate

selected and fixed as mentioned above. We always fill theosteotomy with autologous iliac crest graft. The correct

position of the plate and grafts is confirmed with the

radiographs (Fig. 10). Two drains are placed and thewound is closed in layers [72].

Lateral closing-wedge HTO The procedure typically isperformed with the knee at 90" of flexion. Although

originally the anterolateral aspect of the tibia was

exposed through a long curvilinear incision, a shortoblique or transverse incision extending from the fibular

head toward the tibial tubercle is currently preferred.

After blunt dissection of subcutaneous tissues, we isolatethe peroneal nerve from the tibialis anterior muscular

compartment band to avoid any possible nerve palsy

caused by nerve entrapment after closing of the osteot-omy. The anterolateral portion of the tibial band is

opened and the anterior tibial musculature is elevated

subperiosteally from the proximal tibia. The posteriortibia is subperiosteally exposed to allow insertion of a

broad malleable retractor to protect neurovascular struc-

tures. A guide pin is inserted 2.0–2.5 cm below andparallel to the joint line under fluoroscopic control.

A second pin is inserted distal to the first, running obli-

quely to form an angle that corresponds to the desiredcorrection. The orientation of the second pin either is per-

formed freehand or can be aided by calibrated cutting

guides. The two osteotomy cuts are generally performed

Fig. 9 Medial opening-wedge HTO

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parallel to each other and to the tibial slope in the sagittal

plane. However, the three-dimensional conformation of thebony wedge can be adjusted in the sagittal plane to correct

flexion–extension deformity and tibial slope, by removing

more or less bone anteriorly or posteriorly. Sagittal planecorrection is very important when addressing concomitant

ligamentous instability. After performing the osteotomy, a

sharp osteotome is used to isolate the tibial tuberosity fromthe bony wedge cut in the tibia to allow an easy removal of

the wedge and mobilization of the 2 bony fragments. It isimportant to maintain an intact medial hinge to provide

stability for the osteotomy and to act as a fulcrum during the

reduction maneuver. Removal of a corresponding portion offibular head is then performed with a rongeur, or a fibular

osteotomy is performed. Tibial reduction is now achieved

by applying a valgus stress to the extremity with the knee at10" of flexion. The fibula is inspected to verify that it is not

preventing complete closure of the osteotomy, and rota-

tional alignment is checked. Mechanical alignment is ver-ified by fluoroscopy and fixation is then accomplished with

the insertion of the plate. Counterpressure by a surgical

assistant against the medial tibia during final insertion helpsto prevent tibial translation and disruption of the medial

hinge. After the tourniquet is released, hemostasis is

obtained carefully, with particular attention paid to theregion of the anterior tibial musculature. A suction drain is

placed and the wound is closed in layers [53].

Medial closing-wedge DFO We expose the medial aspect

of the femur with a standard straight incision through the

skin and the subcutaneous tissue along the distal femur tothe femoral epicondyle, taking care to spare the branches of

the anterior femoral cutaneous nerve and the infrapatellar

ramus of the saphenous nerve. The muscle fascia is incisedin line with the skin incision; the sartorious muscle is then

retracted posteriorly and the vastus medialis anteriorly. The

vastus medialis is dissected from the intermuscular septumand retracted anteriorly. Perforators and the plexus-like

periosteal blood vessels are coagulated. The intermuscular

septum in the metaphyseal area of the femur is carefullyincised longitudinally close to the bone. The posterior

aspect of the femur is approached subperiosteally and a

retractor is positioned to protect the neurovascular struc-tures. We leave the joint capsule intact. The lateral cortex

is now exposed.

The authors’ preferred method consists of freehanddrilling of the guide pin, but a positioning plate for varus

osteotomies may be helpful for proper pin placement. In

this case, a pin is inserted parallel to the lower edge of thepositioning plate. Then, the seating chisel with attached

chisel guide is driven into the condyles parallel to the pin to

an average blade length of 60 mm, and then loosenedslightly. The chisel guide should be aligned with the long

axis of the femoral shaft.

The osteotomy is marked at the level of the bend of theplate and is performed with an oscillating saw and/or

osteotome. The three-dimensional conformation of the

bony wedge can be adjusted in the sagittal plane to correctflexion–extension deformity. The guide should deviate

anteriorly from the shaft axis if both varus correction and

anterior angulation are desired; recurvatum deformity iscorrected by moving the guide posteriorly. A half-wedge

resection is sufficient in osteoporotic bone, whereas hard

bone may require the excision of a full-diameter wedge.The seating chisel is replaced with a 90" osteotomy

blade-plate. Only if required, especially in osteoporotic

bone, a cancellous screw can be driven into the distalfragment through the offset of the plate. Then, the osteot-

omy is closed (eventually using an axial tension device),

and the plate secured to the shaft with 4 cortical screws.A suction drain is placed and the wound is closed in layers

[41].

Rehabilitation guidelines

Postoperatively the knee is immobilized with a hinged kneebrace, and CPM is started on day 1. Although progressive

weight-bearing and ROM exercises are vital to recovery,early excessive joint loading and terminal knee flexion–

extension with external loads can compromise the integrity

of the surgical realignment. Patients usually regain full

Fig. 10 Lateral opening-wedge DFO

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motion within the first 4 weeks. After 4 weeks (6 in fem-

oral osteotomy), partial weight-bearing is allowed. Fullweight-bearing is normally possible after 6–7 weeks (8 or 9

in femoral osteotomy) when the radiographs show pro-

gressive healing.

Complications

Intraarticular fracture is a risk, especially with pin

positioning close to the joint, or when excessive force isused to open an osteotomy with incomplete disruption of

the cortex. In this case, the osteotomy should be closed,

thus reducing the fracture, and then the articular-sidedfixation screws are placed, securing both the fracture and

the plate. Thereafter the osteotomy is revisited with the

osteotome, then carefully reopened and the plate fixedwith the remaining screws. Disruption of the contralat-

eral hinge renders the osteotomy quite unstable. Intra-

operative fluoroscopy, especially with stress applied tothe osteotomy after plate placement, can demonstrate

hinge disruption. The hinge should be stabilized with a

staple or small plate to restore mechanical strength of thefixation.

Hardware failure is a rare event, particularly with the

current locking plate systems, but can occur when weight-bearing is advanced too aggressively. Incomplete

engagement of the spacer block in the osteotomy gap

reduces the stiffness and strength of the fixation,increasing the risk of failure. Loss of correction can

occur; however, this is rare with the newer plating sys-

tems. Of course continuing degenerative changes and highadduction moment can contribute to a gradual loss of

correction over time.

Vascular injuries are rare. Accidental injury to theanterior tibial artery has been reported with extensive lat-

eral approaches, or to the posterior vessels unless protected

by the use of a retractor and knee flexion during surgery.Delayed union may occur, but most osteotomies will go on

to union with time and partially assisted early weight-

bearing. Nonunion is also a possibility. In our series, wehad no nonunions, likely due to the systematic use of bone

grafting. While peroneal palsy is a known complication of

closing-wedge HTO, we have never seen this complicationin the opening-wedge technique. However, correction of

severe valgus deformities with DFO can result in transitory

peroneal nerve apraxia.

Results

Even isolated osteotomy has been shown to improve

quality of life in the short to mid-term, with slow deteri-

oration over time. At 5 years, 70–90% of patients report

satisfactory outcomes, which decreases to 50–70% at

15 years [2, 23, 33, 40, 88, 99, 102]. A recent Cochranesystematic review concluded that valgus HTO for knee OA

resulted in significantly less pain and improved WOMAC

score [11]. Postoperative alignment appears critical for thesuccess of osteotomy: patients whose mechanical axis was

corrected to 183–186 degrees (3–6 degrees of valgus)

demonstrated the best long-term outcomes. Overcorrectionresulted in accelerated lateral compartment OA; under-

correction failed to halt progression of medial OA [40].Another study demonstrated 63% survival at 10 years with

correction to less than 5 degrees of valgus, and 94% sur-

vival with correction to greater than 8 degrees [19].Specifically in regard to the treatment of early OA,

results seem to correlate with the preoperative degree of

OA: Ahlback grade 1 demonstrated good or excellentresults in 70% of patients, but only 50 and 40% for grades

2 and 3, respectively [23, 75]. Generally, patients can

expect to maintain their level of sporting activity, eventhough a return to competitive and high-impact activities is

rare [87]. Some studies demonstrated a favorable effect of

osteotomy on articular cartilage even in elderly patients,especially with larger corrections [45, 48, 64]. Several

studies have found no significant differences between

opening- and closing-wedge HTO [10, 94, 95]. Only fewstudies have evaluated combined procedures: Marcacci

et al. evaluated patients (mean age 46 ± 12 years) after

closing-wedge HTO ? medial Menaflex meniscal implantfor meniscus loss after a previous PMM in a varus knee,

founding a significant improvement in clinical outcomes

(Tegner, VAS pain, and Lysholm scores) at 24 monthsminimum follow-up (unpublished data). Linke et al. [50]

compared postmeniscectomy patients treated with HTO

and HTO ? Menaflex, but was unable to demonstratesignificant differences. Verdonk et al. [106] reviewed a

series of meniscal transplants and demonstrated higher

satisfaction in patient with concomitant osteotomy.

Conclusions

Young patients with early OA represent a challenging

population due to a combination of high functionaldemands and limited treatment options. Conservative

measures such as injection and physical therapy can pro-

vide short-term pain relief but are only palliative in nature.Joint replacement, a successful procedure in the older

population, is controversial in younger patients, who are

less satisfied and experience higher failure rates [93, 103].Specifically patients younger than 40 can only expect a

50% chance of good and excellent Knee Society function

scores and a revision rate of 12.5% at 8 years [51].Outcomes of revision arthroplasty are even more guarded

482 Knee Surg Sports Traumatol Arthrosc (2012) 20:468–486

123

[20, 73]: patient satisfaction has been reported as low as

59% [76], and 5-year survival as low as 82% [92].Cartilage repair therefore appears as a potentially

promising treatment alternative for the young patient with

disabling symptoms from early knee OA. While still in itsinfancy, the field of cartilage repair is seeing the rapid

development of new technologies that promise greater ease

of application, less demanding rehabilitation, and betteroutcomes. Concurrent procedures such as meniscal trans-

plantation and osteotomy, however, will remain of crucialimportance to provide a normalized biomechanical envi-

ronment for these new technologies.

Acknowledgments The authors would like to acknowledge GiulioMaria Marcheggiani Muccioli, MD; Rizzoli Orthopaedic Institute,Bologna, Italy; and Aad Dhollander, Ghent University Hospital,Ghent, Belgium.

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